DNS Resolver crashing on fresh factory reset install

After receiving my PfSense SG-4860 unit back from repair, I spent the WE reinstalling it in my network.
The unit is on the latest version (2.4.3-p1) and has been factory reset.
So I started the install from scratch.

I am not sure if, somewhere, I made a change that results in this whole issue, but whether I use the DNS resolver or the DNS Forwarder (I tried with both, not at the same time), the services will stop all the time. As a matter of fact they pretty much stay off. When on, it's for a few seconds at the most.

I can hardly connect to any webpage. When it works, for a few seconds all is good. Otherwise (most of the time) most pages just time out.
I've literally spent the WE trying to troubleshoot the issue and trying to get things to work.

My install is still fairly vanilla:

I created several interfaces and VLANs

I set up the FreeRadius server to assign users to the VLANs

My DNS server (General setup) is currently 1.1.1.1

Pfsense acts as the DHCP server for my network and all my devices have static IPs

My firewall rules are 'allow to any' on all interfaces

I did not install any package other than FreeRadius

While troubleshooting and looking at the logs I also decided to deactivate the DHCPv6 server (but that doesn't help either)

I attached the screenshots of my settings and a few logs.

Does anyone know what I might have done wrong?
I really don't want to reset the whole system and start from scratch.

PS: Just a quick addition: Every couple of hours, for no apparent reason, the DHCP Service goes down again as well. After random periods of time (30 mins, 1H, etc), it turns on again by itself.

Any help greatly appreciated :)

(****** UPATE AUGUST 14 ******)

So I decided to factory reset my unit and start from scratch:

Did the reset and went through the configuration wizard.
Did nothing special in there other than setting Cloudflare as DNS.Finished the wizard and... right away the DNS Resolver starts and stops again.
I also get this error message in the top notification bar now: